Optical pickup device

1. An optical pickup device comprising: a lens holder to support an objective lens; a supporting unit spaced apart from the lens holder; and one or more suspension members, each having one end fixed to the lens holder and another end supported by the supporting unit, to enable a movement of the lens holder, wherein the supporting unit comprises: a fixing member; one or more coupling portions provided in the fixing member to couple each suspension member therein; a magnetic fluid receiving portion disposed in each of the one or more coupling portions and surrounding the suspension member; magnetic fluid disposed in the magnetic fluid receiving portion to surround a portion of each suspension member; and an excite device disposed in the magnetic fluid receiving portion to directly surround the magnetic fluid to apply a magnetic field to the magnetic fluid, the one or more coupling portions comprising: a first coupling portion having a first elastically deformable coupling agent provided therein; a second coupling portion spaced apart from the first coupling portion and having a second elastically deformable coupling agent provided therein; and a space between the first coupling portion and the second coupling portion having the magnetic fluid provided therein.

2. The optical pickup device as claimed in claim 1 , wherein the first elastically deformable coupling agent and the second elastically deformable coupling agent are silicon-based adhesives.

3. The optical pickup device as claimed in claim 1 , wherein the excite device comprises at least one excite coil.

4. The optical pickup device as claimed in claim 3 , wherein the at least one excite coil is provided on at least one of an upper surface, a lower surface, and side surfaces of the fixing member.

5. The optical pickup device as claimed in claim 3 , wherein the at least one excite coil surrounds the magnetic fluid.

6. The optical pickup device as claimed in claim 1 , wherein the magnetic fluid is a colloid solution comprising ferromagnetic particles uniformly dispersed in a fluid.

7. The optical pickup device as claimed in claim 1 , wherein power is supplied to the excite device to apply the magnetic field to the magnetic fluid and control a viscosity of the magnetic fluid and a deformable portion of each suspension member.

8. The optical pickup device as claimed in claim 7 , wherein: a first amount of power is supplied to the excite device to apply a first magnetic field to the magnetic fluid such that the magnetic fluid has a first viscosity and the deformable portion of each suspension member has a first length; and a second amount of power, greater than the first amount of power, is supplied to the excite device to apply a second magnetic field to the magnetic fluid such that the magnetic fluid has a second viscosity, greater than the first viscosity, and the deformable portion of each suspension member has a second length, less than the first length.

9. The optical pickup device as claimed in claim 8 , wherein the first amount of power is supplied to the excite device when an optical disk drive rotates in a low-speed mode and the second amount of power is supplied to the excite device when the optical disk drives rotates in a high-speed mode.

10. The optical pickup device as claimed in claim 7 , wherein the excite device comprises a first excite coil on a first side of the fixing member to apply a first magnetic field and a second excite coil on a second side of the fixing member, different from the first side, to apply a second magnetic field.

11. The optical pickup device as claimed in claim 10 , wherein a first amount of power is supplied to the first excite coil to apply the first magnetic field and a second amount of power, different from the first amount of power, is supplied to the second excite coil to apply the second magnetic field.

12. The optical pickup device of claim 1 wherein the supporting unit controls a change in a natural frequency of each suspension member according to a rotation frequency of the optical disk.

13. A method of stably supporting an objective lens in an optical pickup device the method comprising: fixing a first end of one or more suspension members to a lens holder that holds the objective lens, and a second end of each suspension member to a supporting unit of the optical pickup device to enable a movement of the lens holder; and supplying power to a magnetic fluid surrounding the one or more suspension members in the supporting unit in order to apply a magnetic field to the magnetic fluid and control a length of a deformable portion of each suspension member and supplying the power to at least one excite coil provided on the supporting unit, wherein the at least one excite coil comprises a first excite coil on a first side of the supporting unit to apply a first magnetic field and a second excite coil on a second side of the supporting unit, different from the first side, to apply a second magnetic field, wherein the supplying of the power to the at least one excite coil comprises: supplying a first amount of power to the at least one excite coil when the optical disk drives rotates in a low-speed mode to apply a first magnetic field to the magnetic fluid such that the magnetic fluid has a first viscosity and the deformable portion of each suspension member has a first length; and supplying a second amount of power, greater than the first amount of power, to the at least one excite coil when the optical disk drives rotates in a high-speed mode to apply a second magnetic field to the magnetic fluid such that the magnetic fluid has a second viscosity, greater than the first viscosity, and the deformable portion of each suspension member has a second length, less than the first length.

14. The method as claimed in claim 13 , wherein the at least one excite coif surrounds the magnetic fluid.

15. The method as claimed in claim 13 , wherein the magnetic fluid is a colloid solution comprising ferromagnetic particles uniformly dispersed in a fluid.

16. The method as claimed in claim 13 , wherein the supplying of the power comprises supplying the power to control a viscosity of the magnetic fluid.

17. The method as claimed in claim 13 , wherein the supplying of the power to the at least one excite coil comprises: supplying a first amount of power to the first excite coil to apply the first magnetic field; and supplying a second amount of power, different from the first amount of power, to the second excite coil to apply the second magnetic field.